Pipeline repair

ABSTRACT

In an example, a method of repairing a pipeline includes isolating a section of a pipeline that includes a leak site. The method includes flooding the section of the pipeline with a plug formulation that includes artificial platelets and an ultraviolet (UV) photoinitiator. The section may be pressurized to induce migration of the artificial platelets to the leak site. The method also includes draining excess plug formulation from the section of the pipeline. The method further includes exposing the UV photoinitiator to UV light to form a gas impermeable seal at the leak site.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/932,666, filed Nov. 4, 2015, herein incorporated by reference in itsentirety.

I. FIELD OF THE DISCLOSURE

The present disclosure relates generally to pipeline repair.

II. BACKGROUND

Leaks in pipelines (e.g., natural gas pipelines) may result in aconsiderable amount of gas escaping into the environment. In some cases,pinpointing leaks may be challenging, particularly in the case of buriedpipelines. Further, excavating a buried pipeline to repair leaks may beexpensive or impractical. Additionally, repairing a leak in a gaspipeline may be more challenging than repairing a leak in a liquidpipeline, as a seal or “plug” of a gas pipeline leak may be ineffectiveunless the seal is airtight.

III. SUMMARY OF THE DISCLOSURE

According to an embodiment, a method of repairing a pipeline isdisclosed. The method includes isolating a section of a pipeline thatincludes a leak site and flooding the section of the pipeline with aplug formulation that includes artificial platelets and an ultraviolet(UV) photoinitiator. The method includes pressurizing the section toinduce migration of the artificial platelets to the leak site. Themethod also includes draining excess plug formulation from the sectionof the pipeline. The method further includes exposing the UVphotoinitiator to UV light to form a gas impermeable seal at the leaksite.

According to another embodiment, a plug formulation for repairing apipeline is disclosed. The plug formulation comprises a mixture of anacrylate monomer solution, artificial platelets, and a UVphotoinitiator.

According to another embodiment, a method of repairing a gas pipeline isdisclosed. The method includes identifying a section of a gas pipelinethat includes a leak site and isolating the section of the gas pipeline.The method includes flooding the section of the gas pipeline with a plugformulation that includes a mixture of an acrylate monomer solution,artificial platelets, and a UV photoinitiator. The method also includespressurizing the section of the gas pipeline to induce migration of theartificial platelets to the leak site and draining excess plugformulation from the section of the gas pipeline. The method furtherincludes exposing the UV photoinitiator to UV light to form a gasimpermeable seal at the leak site.

One advantage of the present disclosure is the ability to repair apipeline (e.g., a gas pipeline) using a liquid leak repair formulationthat includes “artificial platelets” that may form a substantially gasimpermeable seal at a leak site. Another advantage of the presentdisclosure is the ability to repair the pipeline without identifyinglocation(s) of leak(s) in the isolated section of pipeline, as an entireisolated section is flooded with the liquid leak repair formulation.

Features and other benefits that characterize embodiments are set forthin the claims annexed hereto and forming a further part hereof. However,for a better understanding of the embodiments, and of the advantages andobjectives attained through their use, reference should be made to theDrawings and to the accompanying descriptive matter.

IV. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagram illustrating a first stage of pipeline repair,according to one embodiment;

FIG. 1B is an expanded view of storage 122, according to one embodiment;

FIG. 1C is an expanded view of leak site(s) 130, according to oneembodiment;

FIG. 2A is a diagram illustrating a second stage of pipeline repair,according to one embodiment;

FIG. 2B is an expanded view of sealing of the leak site by an artificialscab, according to one embodiment; and

FIG. 3 is a flow diagram illustrating an embodiment of a method ofrepairing a pipeline.

V. DETAILED DESCRIPTION

The present disclosure describes fluid formulations for use in repairingpipelines (e.g., gas pipelines, such as buried natural gas pipelines)and methods of repairing pipelines using such fluid formulations. In thepresent disclosure, particles (referred to herein as “artificialplatelets”) that are designed to mimic natural platelets that heal awound by clotting to form a “scab” at a wound site may be used to repaira leak in a pipeline in a similar manner. To illustrate, a section ofpipeline that is identified as having one or more leaks may be isolated,and the section of pipeline may be flooded with a fluid formulation thatincludes the artificial platelets (also referred to herein as a “plugformulation”). Pressurizing the fluid may induce the artificialplatelets in the plug formulation to migrate to a leak site (or multipleleak sites) in order to form a “clot” at the leak site. In some cases,the fluid formulation may include a resin that is curable usingultraviolet (UV) light to form a gas impermeable seal (also referred toherein as an “artificial scab”). After plugging the leak site(s) usingthe artificial platelets, excess plug formulation may be drained fromthe isolated section of pipeline, and an autonomous robot may be used toexpose the UV curable resin to UV light in order to cure the resin.After formation of the artificial scab(s), the autonomous robot may beremoved from the isolated section of pipeline, and the isolated sectionof pipeline may be reconnected. As an alternative example, rather thanflooding the isolated section of pipeline with the plug formulation, theautonomous robot may be deployed to spray coat the interior of thepipeline, and the autonomous robot may be removed. The isolated sectionof pipeline may then be pressurized to force the plug formulation intothe cracks, the pressure may be released, and the autonomous robot maybe redeployed to UV cure the formulation.

While artificial platelets may represent a promising technology forrepair of condensed fluid pipelines (e.g., oil or water), a seal that isformed using artificial platelets alone may be ineffective in thecontext of gas pipelines. To illustrate, the seal may allow natural gasto diffuse around the jammed platelets and eventually leak into thesurrounding environment. In a particular embodiment of the presentdisclosure, a plug formulation may include artificial plateletsincorporated into a multifunctional acrylate monomer solution containinga UV photoinitiator (or multiple initiators). After flooding an isolatedsection of a pipeline with pressurized plug formulation fluid to inducethe artificial platelets to “clot” at the leak site(s), the remainingplug formulation may be drained from the isolated section of thepipeline. UV curing may then be initiated to form a tightly cross-linkednetwork that is substantially impervious to gas diffusion. Thus, in thepresent disclosure, a liquid plug formulation including artificialplatelets may allow for repair of a gas pipeline without expensiveexcavation costs (in the case of a buried pipeline) and withoutisolating individual leaks, as an entire section of pipeline is floodedwith the liquid plug formulation to induce the artificial platelets tofill cracks at each leak site.

Referring to FIG. 1A, a diagram 100 of a first stage of pipeline repairusing a plug formulation of the present disclosure is illustrated. InFIG. 1A, a section of pipeline (e.g., a buried natural gas pipeline)that is identified as having a leak (or multiple leaks) may be isolatedfrom other sections of pipeline. The isolated section of pipeline may beflooded with a liquid plug formulation including artificial plateletsand pressurized. As shown in FIG. 1A, the artificial platelets in theplug formulation may migrate to a leak site (or multiple leak sites) toplug the leak (or multiple leaks). As described further herein withrespect to FIGS. 2A and 2B, after plugging the leak(s), in a particularembodiment an autonomous robot may be deployed to initiate UV curing,resulting in formation of an artificial scab (or multiple scabs) at theplugged leak site (or multiple plugged leak sites) that may besubstantially impervious to gas diffusion.

In the particular embodiment illustrated in FIG. 1A, a pipeline 102includes multiple sections, including a first section 104, a secondsection 106, and a third section 108. As shown in the example of FIG.1A, the first section 104 of the pipeline 102 may be isolated by closinga first valve 110 between the first section 104 and the second section106 and by closing a second valve 112 between the first section 104 andthe third section 108. In the particular embodiment illustrated in FIG.1A, the pipeline 102 is located below ground 114 and may be accessiblevia an access port 116. While not shown in FIG. 1A, it will beappreciated that various equipment may be deployed above the ground 114and/or below the ground 114 in order to enable isolation of and/oraccess to a particular section of the pipeline 102 (e.g., the firstsection 104) without excavation of the pipeline 102. In alternativeembodiments, one or more sections of the pipeline 102 may be above theground 114.

FIGS. 1A and 1B illustrate that the first stage of pipeline repairincludes flooding the first section 104 of the pipeline 102 with aliquid plug formulation 118 that includes artificial platelets 120. Forillustrative purposes only, the artificial platelets 120 of FIG. 1B aredepicted as substantially elliptical shapes having substantially similarsizes. In some cases, the artificial platelets 120 may include a varietyof shapes, sizes, materials, or any combination thereof. As anillustrative, non-limiting example, the artificial platelets 120 mayvary in size from 0.3 to 50 millimeters, with shapes ranging from discsto cubes. In some cases, the “hardness” of the artificial platelets 120may be tailored to a particular pipeline environment. In some cases, amaterial that is too “soft” may be subject to platelet deformation underpressure, resulting in the platelet being “squished” through a leaksite. A material that is too “hard” may not stem the flow of fluid atthe leak site. Thus, it will be appreciated that the artificialplatelets 120 depicted in FIG. 1B represent non-limiting examples ofparticles for purposes of illustrating formation of an artificial clotat one or more cracks in the pipeline 102.

In the example of FIGS. 1A and 1B, the plug formulation 118 is shown instorage 122 and may be introduced into the first section 104 of thepipeline 102 via the access port 116 using a pump 124. As shown by thefluid flow arrows of FIG. 1A, the pump 124 may flood the first section104 of the pipeline 102 with the plug formulation 118 and may pressurizethe first section 104 with fluid. The introduction of the pressurizedfluid may cause the artificial platelets 120 to aggregate at a leak site130, resulting in formation of an artificial clot at the leak site 130.While FIG. 1C depicts an example of an artificial clot being formed at asingle leak site (the leak site 130), it will be appreciated that theintroduction of the pressurized liquid plug formulation 118 into thefirst section 104 of the pipeline 102 may enable formation of multipleartificial clots at multiple leak sites within the first section 104without determining the locations of the leak sites, as the entireinterior of the pipe is exposed to the plug formulation 118.

In a particular embodiment, the plug formulation 118 may include theartificial platelets 120 and a multifunctional acrylate monomer solutioncontaining a UV initiator. As an illustrative, non-limiting example, theplug formulation 118 may include about 50-70 weight percenttrimethylolpropane trimethacrylate (TMPTA) and/or dipentaerythritolpentacrylate; a first photoinitiator for UV curing (e.g., about 2-5weight percent); a second photoinitiator for radical polymerization ofunsaturated resins upon UV light exposure (e.g., about 2-5 weightpercent); and the artificial platelets 120 (e.g., about 20-46 weightpercent).

In another embodiment, the artificial platelets 120 may be induced toswell after forming an initial artificial clot at the leak site(s) 130in order to enhance seal strength. As an illustrative example, theartificial platelets 120 may be formed from a shape memory polymer (SMP)material that expands upon exposure to UV light, moisture, or heat. Toillustrate, the artificial platelets 120 may be formed from aUV-activated shape memory polymer such that exposure to UV light (asillustrated and further described herein with respect to FIGS. 2A and2B) would not only cure the resin but also enlarge the artificialplatelets 120. In this example, enlarging/swelling the artificialplatelets 120 may result in formation of an improved seal at the leaksite(s) 130 compared to the artificial platelets 120 alone. In the caseof SMPs that expand upon exposure to moisture, the plug formulation 118may be pumped into the first section 104, followed by water to induceswelling of the artificial platelets 120. Subsequently, as illustratedand further described herein with respect to FIGS. 2A and 2B, anautonomous robot (among other alternatives, such as fiber optic cables)may be deployed in order to initiate UV curing.

In addition to UV curing, alternative approaches may be used to seal theartificial platelet clot that is formed at the leak site(s) 130. Forexample, the artificial platelets 120 may be cured in place through achemical reaction. To illustrate, a two-part epoxy system may beutilized, where the artificial platelets 120 are carried through thefirst section 104 of the pipeline 102 in solution with one part of theepoxy system. In some cases, the first part of the epoxy system may alsobe covalently bonded to the artificial platelets 120. Subsequently, thesecond part of the epoxy system may be pumped through the first section104 to initiate curing at the clot site. Yet another method may includethe use of a plug formulation that may cure upon mixing but may requiresome time to set. In this case, the formulation may be removed from thepipe before curing is completed, leaving the formulation at the clotsite to cure. As yet another example, a super absorbent polymer may beused to assist in plugging the leak. The super absorbent polymermaterial may expand upon exposure to moisture.

Thus, FIGS. 1A-1C illustrate an example of a first stage of pipelinerepair using the plug formulation of the present disclosure. The firststage of pipeline repair includes the use of a liquid plug formulationthat includes artificial platelets that are designed to mimic naturalplatelets by forming a clot at a pipeline leak site. As describedfurther herein with respect to FIGS. 2A and 2B, after draining excessplug formulation liquid from an isolated section of pipeline, a UVcurable resin in the plug formulation may be cured using UV light inorder to form a substantially gas impermeable artificial scab at theleak site(s) that are plugged with the artificial platelets.

Referring to FIG. 2A, a diagram 200 illustrates a second stage ofpipeline repair that includes draining excess plug formulation from theisolated section of the pipeline and exposing the UV curable resin to UVlight to form a substantially gas impermeable artificial scab. FIG. 2Aillustrates an example in which an autonomous robot 202 is used toexpose the UV curable resin to UV light. In other cases, alternativeequipment (e.g., fiber optic cables) may be used to initiate UV curing.

In the particular embodiment illustrated in FIGS. 2A and 2B, the firstsection 104 of the pipeline 102 remains isolated and has been drained ofexcess plug formulation liquid. FIGS. 2A and 2B illustrate that, afterdraining the first section 104, the autonomous robot 202 may be deployed(e.g., via the access port 116 used to introduce the plug formulation118 or via a different access port) into the first section 104. In FIGS.2a and 2B, the autonomous robot 202 includes a UV light source 204 (ormultiple UV light sources, such as several light “pipes” attached to apressure mercury arc lamp) that emits UV light 206 in order to cure a UVcurable resin 208, resulting in formation of an artificial scab 210(that includes the clot formed by the artificial platelets 120 coveredby a hard layer of cured resin material).

While not shown in FIGS. 2A and 2B, after the autonomous robot 202 hasexposed the UV curable resin 208 to the UV light 206 in order to formthe artificial scab 210, the autonomous robot 202 may be removed fromthe pipeline 102. Subsequently, the isolated first section 104 may bereconnected to the second section 106 of the pipeline 102 (e.g., byopening the first valve 110) and may be reconnected to the third section108 of the pipeline 102 (e.g., by opening the second valve 112).

Thus, FIGS. 2A and 2B illustrates an example of a second stage ofpipeline repair that includes deploying an autonomous robot for UVcuring of a UV curable resin component of the plug formulation (afterdraining excess plug formulation that was introduced into the isolatedsection of the pipeline, as illustrated and described further hereinwith respect to FIGS. 1A-1C). Exposure of the UV curable resin to UVlight may result in an improved seal at a platelet-plugged leak sitethat may reduce the ability of gas in the pipeline (e.g., methane) todiffuse around the clotted artificial platelets and to escape into thesurrounding environment.

Referring to FIG. 3, a particular embodiment of a method 300 of pipelinerepair is illustrated. In the example of FIG. 3, the method 300 includesutilizing a plug formulation that includes a UV curable resin anddeploying an autonomous robot to cure the resin using one or more UVlight sources.

The method 300 includes identifying a section of a pipeline with a leak(or multiple leaks), at 302. For example, referring to FIGS. 1A and 1C,the first section 104 of the pipeline 102 may be identified as havingone or more leaks. In the example of FIG. 1A, the pipeline 102 isillustrated as being buried below the ground 114. In other cases, one ormore sections of the pipeline 102 may be above the ground 114. Further,in some cases, the pipeline 102 may be a gas pipeline (e.g., a naturalgas pipeline), while in other cases the pipeline 102 may be a condensedliquid pipeline (e.g., an oil or water pipeline).

The method 300 includes isolating the section of the pipeline, at 304.For example, referring to FIG. 1A, the first section 104 of the pipeline102 may be isolated from the second section 106 and the third section108 of the pipeline 102. In the particular embodiment illustrated inFIG. 1A, the first section 104 of the pipeline 102 is shown as beingisolated by closing the first valve 110 and the second valve 112. Itwill be appreciated that alternative methods of isolating a particularsection of a pipeline may be used.

The method 300 includes flooding the section of the pipeline with a plugformulation, at 306. For example, referring to FIG. 1A, the firstsection 104 of the pipeline 102 may be flooded with the plug formulation118 by introducing the plug formulation 118 into the isolated firstsection 104 via the access point 116 using the pump 124. While FIG. 1Aillustrates an example of flooding the first section 104 at the accesspoint 116 using the pump 124, it will be appreciated that alternativemethods of introducing the plug formulation 118 into the pipeline 102may be used.

The method 300 includes pressurizing the section of the pipeline, at308. For example, referring to FIG. 1A, the first section 104 of thepipeline 102 may be pressurized with the plug formulation 118 using thepump 124. While FIG. 1A illustrates an example in which pressurizationof the first section 104 includes the introduction of excess liquid plugformulation 118 using the pump 124, in some cases, the pressure in thefirst section 104 may be increased by introducing additional liquidsand/or gases.

The method 300 includes draining the plug formulation from the section,at 310. For example, referring to FIG. 2A, the plug formulation 118illustrated as flooding the first section 104 in FIG. 1A may be drained.While the pump 124 of FIG. 1A is not illustrated in FIG. 2A, in somecases, the plug formulation 118 may be removed from the first section104 using the pump 124. Thus, while FIG. 2A illustrates the firstsection 104 after excess plug formulation 118 has been drained from thefirst section 104, it will be appreciated that an intermediate drainingstage may precede the introduction of the autonomous robot 202 shown inFIG. 2A.

In the particular embodiment illustrated in FIG. 3, the method 300includes deploying an autonomous robot to cure the UV curable resinusing a UV light source (or multiple UV light sources), at 312. Forexample, referring to FIGS. 2A and 2B, the autonomous robot 202 may bedeployed into the isolated first section 104 of the drained pipeline 102via the access port 116. While FIG. 2A illustrates an example in whichthe same access point that is used to introduce the plug formulation 118into the pipeline 102 is used for deployment of the autonomous robot202, it will be appreciated that an alternative access point (e.g., alarger access point) may be used for deployment of the autonomous robot202. FIGS. 2A and 2B illustrate that the autonomous robot 202 mayinclude one or more UV light sources 204 that may be used to initiatecuring of the UV curable resin 208 via exposure to the UV light 206. Asshown in the example of FIG. 2B, curing of the UV curable resin 208 mayresult in formation of the artificial scab 210, sealing the leak site(s)130 in the pipeline 102 in order to reduce/prevent fluid leakage (e.g.,natural gas leakage) into the surrounding environment (e.g., into theground 114 in the case of a buried pipeline).

In the particular embodiment illustrated in FIG. 3, the method 300includes removing the autonomous robot, at 314. For example, while notshown in FIGS. 2A and 2B, after formation of the artificial scab 210,the autonomous robot 202 may be removed from the first section 104 ofthe pipeline 102 (e.g., via the access port 116).

The method 300 includes reattaching the isolated section to thepipeline, at 316. For example, referring to FIG. 2A, after removing theautonomous robot 202, the access port 116 may be closed, the first valve110 may be moved to an open position, and the second valve 112 may bemoved to an open position. As a result, the first section 104 may nolonger be isolated from the second section 106 and the third section 108of the pipeline 102, allowing fluid to flow through the first section104.

Thus, FIG. 3 illustrates an example of a method of repairing a pipelineusing a plug formulation of the present disclosure. In the particularembodiment illustrated in FIG. 3, the plug formulation includesartificial platelets and a UV curable resin, and an autonomous robotwith one or more UV light sources is deployed to cure the resin. Inother embodiments, as described herein, alternative plug formulationsand/or curing methods may be employed in order to form a gas impermeableseal at one or more leak sites of a pipeline.

The previous description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the disclosedembodiments. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thescope of the disclosure. Thus, the present disclosure is not intended tobe limited to the embodiments shown herein but is to be accorded thewidest scope possible consistent with the principles and features asdefined by the following claims.

The invention claimed is:
 1. A method of repairing a pipeline, themethod comprising: isolating a section of the pipeline that includes aleak site; flooding the section of the pipeline with a plug formulationthat includes artificial platelets, an ultraviolet (UV) photoinitiator,and a first part of a two-part epoxy system; pressurizing the section ofthe pipeline to induce migration of the artificial platelets to the leaksite; draining excess plug formulation from the section of the pipeline;pumping a second part of the two-part epoxy system into the section ofthe pipeline to contact the first part of the two-part epoxy system; andexposing the UV photoinitiator to UV light delivered through a fiberoptic cable to form a gas impermeable seal at the leak site.
 2. Themethod of claim 1, wherein the plug formulation further includes amulti-functional acrylate monomer.
 3. The method of claim 1, wherein thepipeline includes a gas pipeline.
 4. The method of claim 1, wherein thepipeline includes a natural gas pipeline.
 5. The method of claim 1,wherein the pipeline includes a buried natural gas pipeline.
 6. Themethod of claim 1, wherein the artificial platelets have acharacteristic dimension in a range of 0.3 millimeters to 50millimeters.
 7. The method of claim 1, wherein the artificial plateletsinclude a first artificial platelet type having a first shape and asecond artificial platelet type having a second shape that is differentfrom the first shape.
 8. The method of claim 1, wherein the artificialplatelets include different platelet types having an elliptical shape, adisc shape, a cube shape, or a combination thereof.
 9. The method ofclaim 2, wherein the artificial platelets are formed from a polymericmaterial that expands upon exposure to the UV light.
 10. The method ofclaim 1, wherein the artificial platelets are formed from a polymericmaterial that expands upon exposure to moisture, the method furthercomprising exposing the section of the pipeline to moisture afterdraining the excess plug formulation from the section of the pipeline.11. The method of claim 10, wherein the polymeric material includes ashape memory polymer material.
 12. The method of claim 10, wherein thepolymeric material includes a super absorbent polymer material.
 13. Themethod of claim 1, wherein the artificial platelets are formed from apolymeric shape memory material that expands upon exposure to heat, themethod further comprising exposing the section of the pipeline to heat.14. A method of repairing a gas pipeline, the method comprising:identifying a section of the gas pipeline that includes a leak site;isolating the section of the gas pipeline; flooding the section of thegas pipeline with a plug formulation that includes artificial platelets,an ultraviolet (UV) photoinitiator, and a first part of a two-part epoxysystem, a portion of the first part of the two-part epoxy system iscovalently bonded to a portion of the artificial platelets; pressurizingthe section of the gas pipeline to induce migration of the artificialplatelets to the leak site; draining excess plug formulation from thesection of the gas pipeline; pumping a second part of the two-part epoxysystem into the section of the gas pipeline to contact the first part ofthe two-part epoxy system; and exposing the UV photoinitiator to UVlight delivered through a fiber optic cable to form a gas impermeableseal at the leak site.
 15. The method of claim 14, wherein the gaspipeline includes a buried natural gas pipeline, and wherein the sectionis flooded with the plug formulation without identifying a location ofthe leak site within the buried natural gas pipeline.
 16. The method ofclaim 14, wherein the plug formulation further includes amulti-functional acrylate monomer.
 17. The method of claim 16, whereinthe artificial platelets are formed from a polymeric material thatexpands upon exposure to the UV light.